Various kinds of configurations have been developed as the fluid delivery systems for delivering a fluid from one container to another container, and those kinds of fluid delivery systems are used when delivering various kinds of fluids in studies of chemistry and biology, product manufacture, medical services, and the like, for example (JP-A No. 2011-6466, JP-T No. 2007-526424).
In the work of cell culture, cultured cells and a fluid such as a used medium and the like (referred to as a waste fluid hereinafter) are separated by means of settling, centrifugation, or the like, and the waste fluid is aspirated by a pump and delivered to a waste fluid storage container.
Conventionally, a vacuum pump is used for the work of aspirating the waste fluid. With the vacuum pump, the delivered waste fluid is stored in a waste fluid storage container such as a waste fluid bottle or the like. When a specific amount is stored or a series of work is completed, the waste fluid storage container such as the waste fluid bottle and a fluid delivering part such as a fluid delivery tube connecting to the waste fluid storage container from a aspiration part need to be detached and also the waste fluid stored in the waste fluid storage container needs to be transferred to a disposable container through decantation or the like. In that case, the waste fluid may be splashed and may contaminate the workspace.
Also, when aspirating the waste fluid, it is required to discard the waste fluid without influencing the cultured cells. For satisfying such demand, in a case where the amount of the waste fluid is great within one container, there is no influence imposed upon the cultured cells even when the waste fluid is aspirated abruptly since the aspiration port of the delivery pump is distant from the cultured cells. However, when the waste fluid is disposed and the remaining amount of the waste fluid becomes small, the aspiration port of the delivery pump becomes closer to the cultured cells. Therefore, it is necessary to slow the aspiration speed of the delivery pump.
As described, in order to control the aspiration speed of the delivery pump, it is necessary to control the feed speed of the delivery pump. In order to control the feed speed of the delivery pump, it is common to output control values for controlling the feed speed linearly.